diff --git a/STATUS.md b/STATUS.md
index 98646059..328b8215 100644
--- a/STATUS.md
+++ b/STATUS.md
@@ -174,53 +174,54 @@ Floating point mathematical routines - not official, but well known and broadly
-| Address | Name | Status | Remarks |
-| :-------: | :----------------- | :------: | :------------------------------------------------: |
-| `$B1AA` | `FACINX` | NOT DONE | convert FAC1 to 16-bit signed integer |
-| `$B391` | `GIVAYF` | NOT DONE | 16-bit signed integer to FAC1 |
-| `$B7B5` | `STRVAL` | NOT DONE | imports string to FAC1 |
-| `$B850` | `sub_MEM_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
-| `$B853` | `sub_FAC2_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
-| `$B867` | `add_MEM_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
-| `$B86A` | `add_FAC2_FAC1` | NOT DONE | |
-| `$B8FE` | `normal_FAC1` | PARTIAL | not tested yet |
-| `$B9EA` | `log_FAC1` | NOT DONE | |
-| `$BA28` | `mul_MEM_FAC1` | PARTIAL | needs `mul_FAC2_FAC1` |
-| `$BA2B` | `mul_FAC2_FAC1` | NOT DONE | |
-| `$BA8C` | `mov_MEM_FAC2` | PARTIAL | not fully tested yet |
-| `$BAE2` | `mul10_FAC1` | NOT DONE | |
-| `$BAFE` | `div10_FAC1_p` | NOT DONE | |
-| `$BB0F` | `div_MEM_FAC1` | PARTIAL | needs `div_FAC2_FAC1` |
-| `$BB12` | `div_FAC2_FAC1` | NOT DONE | |
-| `$BBA2` | `mov_MEM_FAC1` | PARTIAL | not fully tested yet |
-| `$BBC7` | `mov_r_FAC1_TMP2` | PARTIAL | not fully tested yet |
-| `$BBCA` | `mov_r_FAC1_TMP1` | PARTIAL | not fully tested yet |
-| `$BBD0` | `mov_r_FAC1_VAR` | PARTIAL | not fully tested yet |
-| `$BBD4` | `mov_r_FAC1_MEM` | PARTIAL | not fully tested yet |
-| `$BBFC` | `mov_FAC2_FAC1` | PARTIAL | not fully tested yet |
-| `$BC0C` | `mov_r_FAC1_FAC2` | PARTIAL | not fully tested yet |
-| `$BC0F` | `mov_FAC1_FAC2` | DONE | |
-| `$BC1B` | `round_FAC1` | PARTIAL | not fully tested yet |
-| `$BC2B` | `sgn_FAC1_A` | NOT DONE | |
-| `$BC39` | `sgn_FAC1` | NOT DONE | |
-| `$BC58` | `abs_FAC1` | NOT DONE | |
-| `$BC5B` | `FCOMP` | NOT DONE | compare FAC1 with RAM location |
-| `$BC9B` | `QINT` | NOT DONE | convert FAC1 to 32 bit signed integer |
-| `$BCCC` | `int_FAC1` | NOT DONE | |
-| `$BCF3` | `FIN` | NOT DONE | imports string to FAC1, ignores spaces |
-| `$BDDD` | `FOUT` | NOT DONE | outputs FAC1 to string at $0100 |
-| `$BF71` | `sqr_FAC1` | NOT DONE | |
-| `$BF74` | `sqr_FAC2` | NOT DONE | |
-| `$BF78` | `FPWR` | NOT DONE | set FAC1 as RAM raised to the power of FAC1 |
-| `$BF7B` | `FPWRT` | NOT DONE | set FAC1 as FAC2 raised to the power of FAC1 |
-| `$BFB4` | `toggle_sign_FAC1` | DONE | |
-| `$BFED` | `exp_FAC1` | NOT DONE | |
-| `$E043` | `poly1_FAC1` | NOT DONE | |
-| `$E059` | `poly2_FAC1` | NOT DONE | |
-| `$E264` | `cos_FAC1` | NOT DONE | |
-| `$E26B` | `sin_FAC1` | NOT DONE | |
-| `$E2B4` | `tan_FAC1` | NOT DONE | |
-| `$E30E` | `atn_FAC1` | NOT DONE | |
+| Address | Name | Status | Remarks |
+| :-------: | :-------------------- | :------: | :------------------------------------------------: |
+| `$B1AA` | `FACINX` | NOT DONE | convert FAC1 to 16-bit signed integer |
+| `$B391` | `GIVAYF` | NOT DONE | 16-bit signed integer to FAC1 |
+| `$B7B5` | `STRVAL` | NOT DONE | imports string to FAC1 |
+| `$B850` | `sub_MEM_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
+| `$B853` | `sub_FAC2_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
+| `$B862` | `add_align_exponents` | PARTIAL | not tested yet |
+| `$B867` | `add_MEM_FAC1` | PARTIAL | needs `add_FAC2_FAC1` |
+| `$B86A` | `add_FAC2_FAC1` | NOT DONE | |
+| `$B8FE` | `normal_FAC1` | PARTIAL | not tested yet |
+| `$B9EA` | `log_FAC1` | NOT DONE | |
+| `$BA28` | `mul_MEM_FAC1` | PARTIAL | needs `mul_FAC2_FAC1` |
+| `$BA2B` | `mul_FAC2_FAC1` | NOT DONE | |
+| `$BA8C` | `mov_MEM_FAC2` | PARTIAL | not fully tested yet |
+| `$BAE2` | `mul10_FAC1` | NOT DONE | |
+| `$BAFE` | `div10_FAC1_p` | NOT DONE | |
+| `$BB0F` | `div_MEM_FAC1` | PARTIAL | needs `div_FAC2_FAC1` |
+| `$BB12` | `div_FAC2_FAC1` | NOT DONE | |
+| `$BBA2` | `mov_MEM_FAC1` | PARTIAL | not fully tested yet |
+| `$BBC7` | `mov_r_FAC1_TMP2` | PARTIAL | not fully tested yet |
+| `$BBCA` | `mov_r_FAC1_TMP1` | PARTIAL | not fully tested yet |
+| `$BBD0` | `mov_r_FAC1_VAR` | PARTIAL | not fully tested yet |
+| `$BBD4` | `mov_r_FAC1_MEM` | PARTIAL | not fully tested yet |
+| `$BBFC` | `mov_FAC2_FAC1` | PARTIAL | not fully tested yet |
+| `$BC0C` | `mov_r_FAC1_FAC2` | PARTIAL | not fully tested yet |
+| `$BC0F` | `mov_FAC1_FAC2` | DONE | |
+| `$BC1B` | `round_FAC1` | PARTIAL | not fully tested yet |
+| `$BC2B` | `sgn_FAC1_A` | NOT DONE | |
+| `$BC39` | `sgn_FAC1` | NOT DONE | |
+| `$BC58` | `abs_FAC1` | NOT DONE | |
+| `$BC5B` | `FCOMP` | NOT DONE | compare FAC1 with RAM location |
+| `$BC9B` | `QINT` | NOT DONE | convert FAC1 to 32 bit signed integer |
+| `$BCCC` | `int_FAC1` | NOT DONE | |
+| `$BCF3` | `FIN` | NOT DONE | imports string to FAC1, ignores spaces |
+| `$BDDD` | `FOUT` | NOT DONE | outputs FAC1 to string at $0100 |
+| `$BF71` | `sqr_FAC1` | NOT DONE | |
+| `$BF74` | `sqr_FAC2` | NOT DONE | |
+| `$BF78` | `FPWR` | NOT DONE | set FAC1 as RAM raised to the power of FAC1 |
+| `$BF7B` | `FPWRT` | NOT DONE | set FAC1 as FAC2 raised to the power of FAC1 |
+| `$BFB4` | `toggle_sign_FAC1` | DONE | |
+| `$BFED` | `exp_FAC1` | NOT DONE | |
+| `$E043` | `poly1_FAC1` | NOT DONE | |
+| `$E059` | `poly2_FAC1` | NOT DONE | |
+| `$E264` | `cos_FAC1` | NOT DONE | |
+| `$E26B` | `sin_FAC1` | NOT DONE | |
+| `$E2B4` | `tan_FAC1` | NOT DONE | |
+| `$E30E` | `atn_FAC1` | NOT DONE | |
diff --git a/c64/basic/math/add_align_exponents.s b/c64/basic/math/add_align_exponents.s
new file mode 100644
index 00000000..3956ed9c
--- /dev/null
+++ b/c64/basic/math/add_align_exponents.s
@@ -0,0 +1,169 @@
+// #LAYOUT# STD * #TAKE
+// #LAYOUT# * BASIC_0 #TAKE
+// #LAYOUT# * * #IGNORE
+
+//
+// Math package - align FAC1 and FAC2 exponents for addition
+//
+// See also:
+// - [CM64] Computes Mapping the Commodore 64 - page 115
+// - https://www.c64-wiki.com/wiki/BASIC-ROM
+
+// XXX finish and test this
+
+add_align_exponents:
+
+ // XXX assume here none of the exponents is 0, check if this is true for orignal ROMs
+
+ lda FAC1_exponent
+ cmp FAC2_exponent
+ beq add_align_exponents_done // branch if exponents the same
+ bcs add_align_exponent_FAC2
+
+ // FALLTROUGH
+
+add_align_exponent_FAC1:
+
+ // First check the exponent difference
+
+ lda FAC2_exponent
+ sec
+ sbc FAC1_exponent
+
+ cmp #$28
+ bcs add_align_exponent_FAC1_zero // branch if difference is very high
+
+ cmp #$08
+ bcc add_align_exponent_FAC1_bit
+
+ // FALLTROUGH
+
+add_align_exponent_FAC1_byte:
+
+ // Add 8 to exponent, divide mantissa by 256
+
+ lda FAC1_exponent
+ clc
+ adc #$08
+ sta FAC1_exponent
+
+ lda FAC1_mantissa+3
+ sta FACOV
+ lda FAC1_mantissa+2
+ sta FAC1_mantissa+3
+ lda FAC1_mantissa+1
+ sta FAC1_mantissa+2
+ lda FAC1_mantissa+0
+ sta FAC1_mantissa+1
+ lda #$00
+ sta FAC1_mantissa+0
+
+ beq add_align_exponent_FAC1 // branch always - next iteration
+
+add_align_exponent_FAC1_bit:
+
+ // Increment exponent, divide mantissa by 2
+
+ inc FAC1_exponent
+
+ clc
+ ror FAC1_mantissa+0
+ ror FAC1_mantissa+1
+ ror FAC1_mantissa+2
+ ror FAC1_mantissa+3
+ ror FACOV
+
+ lda FAC1_exponent
+ cmp FAC2_exponent
+ bne add_align_exponent_FAC1_bit // branch if next iteration needed
+
+ rts
+
+add_align_exponent_FAC1_zero:
+
+ lda #$00
+
+ sta FAC1_mantissa+0
+ sta FAC1_mantissa+1
+ sta FAC1_mantissa+2
+ sta FAC1_mantissa+3
+ sta FACOV
+
+ lda FAC2_exponent
+ sta FAC1_exponent
+
+ // FALLTROUGH
+
+add_align_exponents_done:
+
+ rts
+
+
+
+add_align_exponent_FAC2:
+
+ // First check the exponent difference, Carry already set here
+
+ lda FAC1_exponent
+ sbc FAC2_exponent
+
+ cmp #$20
+ bcs add_align_exponent_FAC2_zero // branch if difference is very high
+
+ cmp #$08
+ bcc add_align_exponent_FAC2_bit
+
+ // FALLTROUGH
+
+add_align_exponent_FAC2_byte:
+
+ // Add 8 to exponent, divide mantissa by 256
+
+ lda FAC2_exponent
+ clc
+ adc #$08
+ sta FAC2_exponent
+
+ lda FAC2_mantissa+2
+ sta FAC2_mantissa+3
+ lda FAC2_mantissa+1
+ sta FAC2_mantissa+2
+ lda FAC2_mantissa+0
+ sta FAC2_mantissa+1
+ lda #$00
+ sta FAC2_mantissa+0
+
+ beq add_align_exponent_FAC2 // branch always - next iteration
+
+add_align_exponent_FAC2_bit:
+
+ // Increment exponent, divide mantissa by 2
+
+ inc FAC2_exponent
+
+ clc
+ ror FAC2_mantissa+0
+ ror FAC2_mantissa+1
+ ror FAC2_mantissa+2
+ ror FAC2_mantissa+3
+
+ lda FAC1_exponent
+ cmp FAC2_exponent
+ bne add_align_exponent_FAC2_bit // branch if next iteration needed
+
+ rts
+
+
+add_align_exponent_FAC2_zero:
+
+ lda #$00
+
+ sta FAC2_mantissa+0
+ sta FAC2_mantissa+1
+ sta FAC2_mantissa+2
+ sta FAC2_mantissa+3
+
+ lda FAC1_exponent
+ sta FAC2_exponent
+
+ rts
diff --git a/c64/basic/math/b862.add_align_exponent.jmp.s b/c64/basic/math/b862.add_align_exponent.jmp.s
new file mode 100644
index 00000000..bcddf0ba
--- /dev/null
+++ b/c64/basic/math/b862.add_align_exponent.jmp.s
@@ -0,0 +1,8 @@
+// #LAYOUT# STD * #TAKE
+// #LAYOUT# * BASIC_0 #TAKE
+// #LAYOUT# * * #IGNORE
+
+// Just a compatibility jump - our routine is longer than original one
+
+
+ jmp add_align_exponents
diff --git a/c64/basic/math/b862.interop b/c64/basic/math/b862.interop
new file mode 100644
index 00000000..0d18777c
--- /dev/null
+++ b/c64/basic/math/b862.interop
@@ -0,0 +1,3 @@
+This is an important floating point math routine, documented in many places.
+
+XXX - try to find real-life example
diff --git a/c64/basic/math/mov_FAC1_MEM.s b/c64/basic/math/mov_FAC1_MEM.s
index 9a8621fb..84d49903 100644
--- a/c64/basic/math/mov_FAC1_MEM.s
+++ b/c64/basic/math/mov_FAC1_MEM.s
@@ -19,11 +19,8 @@
mov_FAC1_MEM:
- // Checked in the available documentation:
- // - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
- // - https://www.lemon64.com/forum/viewtopic.php?t=67576&sid=d41e77cdddd28d6f9c9d52ce5b4e8dc3
- // that $22/$23 (INDEX+0 and INDEX+1) are at least sometimes used for pointer storage.
- // Confirmed by experimenting with original ROM that this is the case here too.
+ // Original routines use $22/$23 location for a vector too, see here:
+ // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
sty INDEX+1
stx INDEX+0
diff --git a/c64/basic/math/mov_MEM_FAC1.s b/c64/basic/math/mov_MEM_FAC1.s
index 14ceb648..39296f87 100644
--- a/c64/basic/math/mov_MEM_FAC1.s
+++ b/c64/basic/math/mov_MEM_FAC1.s
@@ -23,11 +23,8 @@
mov_MEM_FAC1:
- // Checked in the available documentation:
- // - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
- // - https://www.lemon64.com/forum/viewtopic.php?t=67576&sid=d41e77cdddd28d6f9c9d52ce5b4e8dc3
- // that $22/$23 (INDEX+0 and INDEX+1) are at least sometimes used for pointer storage.
- // Confirmed by experimenting with original ROM that this is the case here too.
+ // Original routines use $22/$23 location for a vector too, see here:
+ // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
sty INDEX+1
sta INDEX+0
diff --git a/c64/basic/math/mov_MEM_FAC2.s b/c64/basic/math/mov_MEM_FAC2.s
index 0258c041..8102794d 100644
--- a/c64/basic/math/mov_MEM_FAC2.s
+++ b/c64/basic/math/mov_MEM_FAC2.s
@@ -26,11 +26,8 @@
mov_MEM_FAC2:
- // Checked in the available documentation:
- // - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
- // - https://www.lemon64.com/forum/viewtopic.php?t=67576&sid=d41e77cdddd28d6f9c9d52ce5b4e8dc3
- // that $22/$23 (INDEX+0 and INDEX+1) are at least sometimes used for pointer storage.
- // Confirmed by experimenting with original ROM that this is the case here too.
+ // Original routines use $22/$23 location for a vector too, see here:
+ // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
sty INDEX+1
sta INDEX+0
diff --git a/c64/basic/math/normal_FAC1.s b/c64/basic/math/normal_FAC1.s
index 0dda7581..5dc96fa5 100644
--- a/c64/basic/math/normal_FAC1.s
+++ b/c64/basic/math/normal_FAC1.s
@@ -16,30 +16,32 @@
normal_FAC1:
lda FAC1_exponent
- beq normal_FAC1_end // branch if our float is 0
+ beq normal_FAC1_end // branch if our float is 0
- lda FAC1_mantissa+3
- beq normal_FAC1_by_byte // branch if we can move the whole byte
+ // FALLTROUGH
+
+normal_FAC1_check_mantissa_byte:
+
+ lda FAC1_mantissa+0
+ beq normal_FAC1_by_byte // branch if we can move the whole byte
+ // FALLTROUGH
+
+normal_FAC1_check_mantissa_bit:
+
+ lda FAC1_mantissa+0 // XXX optimize for 65CE02?
and #$80
- bne normal_FAC1_end // branch if already normalized
+ bne normal_FAC1_end // branch if already normalized
// FALLTROUGH
normal_FAC1_by_bit:
- // First check the current exponent
+ // Decrement the exponent
- lda FAC1_exponent
- cmp #$01
- bne !+
-
- // Exponent is 1 - just mark the whole number as 0 and finish
-
- lda #$00
- sta FAC1_exponent
- rts
-!:
+ dec FAC1_exponent
+ beq normal_FAC1_end // exponent reached 0, nothing more to do
+
// Multiply the mantissa by 2
clc
@@ -49,7 +51,7 @@ normal_FAC1_by_bit:
rol FAC1_mantissa+1
rol FAC1_mantissa+0
- bcc normal_FAC1 // branch if next iteration needed
+ bcc normal_FAC1_check_mantissa_bit // branch if next iteration needed
rts
normal_FAC1_by_byte:
@@ -63,19 +65,19 @@ normal_FAC1_by_byte:
lda #$00
!:
sta FAC1_exponent
- beq normal_FAC1_end // branch if our float reached 0
+ beq normal_FAC1_end // branch if our float reached 0
// Now multiply the mantissa by 8 by moving the whole bytes
- lda FAC1_mantissa+2
- sta FAC1_mantissa+3
lda FAC1_mantissa+1
- sta FAC1_mantissa+2
- lda FAC1_mantissa+0
+ sta FAC1_mantissa+0
+ lda FAC1_mantissa+2
sta FAC1_mantissa+1
+ lda FAC1_mantissa+3
+ sta FAC1_mantissa+2
lda FACOV
- sta FAC1_mantissa+0
+ sta FAC1_mantissa+3
lda #$00
sta FACOV
@@ -87,7 +89,7 @@ normal_FAC1_by_byte:
ora FAC1_mantissa+2
ora FAC1_mantissa+3
- bne normal_FAC1 // not 0 - branch to next iteration
+ bne normal_FAC1_check_mantissa_byte // not 0 - branch to next iteration
// Our mantissa reached 0 - mark exponent as 0 and finish